diff --git a/Makefile b/Makefile
index 03e1c60..1e5aae3 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,8 @@
 CFLAGS=-std=c99
+INDENTOPTS=-kr --no-tabs --braces-on-func-def-line --indent-level2
 
 all: approximate-pi
+
+.PHONY: indent
+indent:
+	indent $(INDENTOPTS) *.c
diff --git a/approximate-pi.c b/approximate-pi.c
index 7c37b7b..feeabd2 100644
--- a/approximate-pi.c
+++ b/approximate-pi.c
@@ -5,11 +5,11 @@ double approximate_pi(unsigned int steps) {
   double approximate_pi = 4.0;
   bool subtract = true;
 
-  for(int i=2; i<=steps; i++) {
+  for (int i = 2; i <= steps; i++) {
     if (subtract) {
-      approximate_pi -= (4.0/(i*2-1));
+      approximate_pi -= (4.0 / (i * 2 - 1));
     } else {
-      approximate_pi += (4.0/(i*2-1));
+      approximate_pi += (4.0 / (i * 2 - 1));
     }
     subtract = !subtract;
   }